Judgment and common sense of fluoride deficiency in central air conditioning

Central air conditioning
The amount of fluoride added to large central air conditioners is generally more, and there are more types of refrigerants. The specific amount can be added according to the label on the nameplate. It is necessary to grasp the amount.

1. Determine whether the central air conditioner lacks fluoride
1. After turning on the indoor unit for more than ten minutes, you should see that the evaporator (the copper tube is covered with aluminum sheets for heat exchange) is evenly covered with condensed water (like dew), which is normal (air humidity More often than not, and vice versa). If half of them do not exist, it may be a lack of fluoride, such as local frost or ice is not normal. The trachea valve is dry. No obvious cooling sensation when touched by hand. The reason is the lack of fluorine, which causes the boiling point of the refrigerant in the evaporator to decrease, causing the heat of the refrigerant in the valve to increase and the temperature of the valve to increase.
2. Use a thermometer to measure the temperature difference between the inlet and outlet of the indoor unit. The difference is more than 8 ℃. The larger the temperature difference is, the better the air conditioner works. After the air conditioner is turned on normally for a period of time, the wind blowing on the body feels cool and can quickly reach the set temperature. The outdoor compressor can be turned on and stopped like a refrigerator for a while, which can be said to be normal.
3. If the outdoor unit is within the reach of human hands, it can be touched by hand after being turned on for more than ten minutes. The outdoor unit has two copper valves, one connected to the thick copper pipe and the other connected to the thin copper pipe. Touching the two valves by hand should have a temperature difference; the thicker one should be lower than the thinner one, and it is normal to feel cooler (there should also be condensed water when the temperature is high). Then touch the hot air of the outdoor unit if it is hot. High fever may lack fluoride. Users who have used it for more than half a year can check whether there are obvious signs of oil leakage at the pipe joints of the indoor unit and the valves of the outdoor unit. , Leaky fluorine must leak oil.
4. The liquid pipe valve is frosted. The reason is the lack of fluorine, which causes the pressure in the liquid pipe to drop and the boiling point to decrease, which makes the valve temperature lower than the freezing point. Open the indoor unit panel and remove the filter, you can find that only a small part of the evaporator is frosted. This is the result of insufficient refrigerant and a corresponding reduction in cooling area.
Second, the central air-conditioning step
1. The newly installed central air conditioner must be evacuated before adding fluoride. According to the size of the system, two 8-liter vacuum pumps are used for continuous 24 hours. If the system is larger, add another vacuum pump. Until the vacuum is pumped to minus 40, the vacuum meets the requirements.
2. Add refrigerant from the high pressure side, which is also called static fluoride method, until it can not be added, and then slowly add from the low pressure side after starting, after a while, stop and observe for half an hour, if not enough, add Repeatedly, it can not be added all the time, because when the refrigeration is added, there is no gasification, the press is inaccurate, and sometimes it cannot be seen. When it is added, the pressure is enough, but when it is actually cooled, the pressure is relatively high, which is equal to Add more.
3. Fluorine supplement method of central air conditioner
1. After using the central air conditioner for several years, it is found that the cooling effect is not as good as before, and the pressure is not enough. Then a certain amount of refrigerant must be added to achieve the desired cooling effect.
2. When replenishing, it should be added slowly from the low pressure side while running. It can be replenished according to the actual situation of the pressure. The temperature of the head of the compressor, the return air temperature, and the exhaust temperature should be measured while adding. Water temperature.
3. Open the central air conditioner by one degree. If you do n’t have enough experience, add one or two barrels, the pressure and current will not change much, because the storage system of the large central air conditioner is relatively large, even if you add 10 Barrel 8 barrel pressure changes are not large.
4. Precautions for adding fluoride to air conditioners
1. Open the air conditioner
When the fluoride is added in summer, the air conditioner can be operated in cooling mode directly. Because the fluoride operation cannot be performed under heating conditions, when adding fluoride in winter, the method of heating the reversing valve line is used to force the air conditioner to enter the cooling state.
2. Connect the fluoride equipment
After the air conditioner starts normally, connect the fluoride equipment from the process port on the low-pressure valve side of the outdoor unit. During this process, the air and dirt in the fluoride tube must be removed.
3. Pressure measurement plus fluoride
Check the low-pressure pressure in summer, when the ambient temperature is about 32 degrees Celsius, the pressure is controlled at about 0.45MP; in winter, the high-pressure pressure during heating is investigated, and the pressure is stabilized at about 1.7MP.
4. Remove the fluoride equipment
In the cooling state, remove the fluoride equipment, and tighten the external machine to seal the container; if the equipment is removed in the heating state, a lot of freon leakage will form.

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